The management of some State-owned companies has been criticized for mistreating employees after it emerged that 11 migrant workers were fed leftovers at a Beijing construction site.

Xu Deming, vice chairman of the All-China Federation of Trade Unions, said yesterday that some State-owned firms failed to show respect to their workers and added they should be "morally condemned."

He added that trade unions were seeking to enhance their influence among migrant workers and help curb incidents in which they were treated badly.

According to previous reports, 11 migrant workers employed by China Construction Second Engineering Bureau found leftovers including gnawed chicken bones, fish bones and broken eggs in their meals over two days earlier this month.

One worker, Wang Junjie, kept a 5-centimeter-long fish bone as evidence, and the chef has since been fired.

The incident sparked debate among tens of thousands of people on the Internet when the story broke.

Health officials said serving leftovers did not breach the law, but added that providing stale or unhygienic food was illegal.

Following the involvement of the All-China Federation of Trade Unions and local trade union organizations, management officials at the construction site and the workers' employer apologized.

"The incident shows the management at some State-owned companies has little knowledge of showing respect to their employees," Xu said.

"They failed to put workers first and should be morally condemned."

He added his organization and some State departments had demanded that working conditions of migrant workers be improved prior to the incident.

The organization has previously pledged to have 10 specific projects in place by the end of this year to safeguard the rights and interests of China's approximate 150 million migrant workers.

They include pressing employers to sign labor contracts with workers, providing greater help to those whose rights have been infringed upon, and ensuring they are fully paid.

"But we might not have promoted ourselves enough among migrant workers," Xu said. "Workers sometimes don't have a clear understanding of what trade unions could do for them."